The study evaluated the seeding quality of radish seeds cv. Saxa Polana (percentage of single seeds, double seeds and missed seeds (skips) sown with a Max Pneumatic S 156 seed drill fitted with a pneumatic seed dosing unit set at different forward speeds of a metering unit and different sowing disc speeds. The seeding quality was analysed using Nakagami distribution functions, a chi-squared goodness of fit test, linear regression functions, and the ISO 7256/1, 1984 (E) Standard. The diagrams predicting the effect of the different speeds on the percentage of singles, doubles and skips were highly consistent with the results of the seeding quality analysis based on the ISO 7256/1, 1984 (E) Standard. The authors relied on Nakagami distribution functions to develop a new method for predicting the in-row distance between seeds within the analysed range of speeds, including those which were not empirically tested speeds. The proposed method can be used to predict seeding quality at different speeds when only the selected settings of the dosing unit are taken into account in the analysis. This approach significantly shortens the research time and also decreases the relevant costs.